3D printing is an additive manufacturing process. Printing or manufacturing an object is a process of adding material layer by layer. Each layer could be added on top of an earlier printed layer or on the bottom of an earlier printed layer. The printing process is relatively straightforward, when a simple object with straight and vertical walls, such as a parallelepiped or a similar object should be printed. However, most objects are not so simple in structure and include curved surfaces and surfaces that could overhang outside the main body of the object or in case a hollow object, protrude into a hollow void or cavity inside the object defined by the object walls. The surfaces could be inclined, oriented at different angles and have different thicknesses or sizes. Different size material layers (narrower or broader) could be required to print such objects.
Printing or manufacture of such protruding or overhanging surfaces is usually accomplished by introduction of so called support structures similar to scaffolds used in building construction. Some of the scaffolds, especially these that affect object appearance are removed after object completion and others could remain.
Different techniques are used to determine and print the scaffolding or support structures. Usually, the support structures are made of the same material of which the 3D object is made, although use of other and different materials is known, for example U.S. Pat. No. 8,974,213 to the same assignee discloses use for support structure of different material than the material the 3D object is made.
Some of the printers automatically create support structures. For more complex objects operator intervention could be required. This slows down the 3D object generation process and largely depends on the operator expertise.
Methods for manufacture of such supports or reinforcement structures are described for example, in U.S. Pat. Nos. 5,595,703; 6,797,351; 8,285,411; and US Patent Application Publication 2010/0042241.